This report analyses selected public expenditure programmes supporting environmental investments in water supply and wastewater treatment infrastructure in four OECD countries: Austria, Belgium (the Region of Flanders), France and Germany. These programmes have been selected as they involve different approaches to managing public expenditure for water investments. The study focuses on mechanisms for managing government assistance at both national (Austria) and sub-national (Belgium, France, Germany) levels. In selecting the case studies, special attention has been given to the relevance of the expenditure programmes in their national environment and economic policy regimes as well as the potential for replication of good practices in transition economies.